Functionality - ABB Relion Technical Manual

Section 8
Current protection
8.2.2
8.2.3
204

Functionality

The four step residual overcurrent protection, zero or negative sequence direction
(EF4PTOC, 51N/67N) has independent inverse time delay settings for step 1 and 4. Step
2 and 3 are always definite time delayed.
All IEC and ANSI inverse time characteristics are available.
EF4PTOC (51N/67N) can be set directional or non-directional independently for each of
the steps.
The directional part of the function can be set to operate on following combinations:
• Directional current (I3PDir) versus Polarizing voltage (V3PPol)
• Directional current (I3PDir) versus Polarizing current (I3PPol)
• Directional current (I3PDir) versus Dual polarizing (VPol+ZPol x IPol) where ZPol
= RPol + jXPol
IDir, VPol and IPol can be independently selected to be either zero sequence or negative
sequence.
Other setting combinations are possible, but not recommended.
Second harmonic blocking level can be set for the function and can be used to block each
step individually.
Function block
EF4PTOC (51N_67N)
I3P* TRIP
V3P* TRST1
I3PPOL* TRST2
I3PDIR* TRST3
BLOCK TRST4
BLK1 BFI_3P
BLK2 PU_ST1
BLK3 PU_ST2
BLK4 PU_ST3
PU_ST4
PUFW
PUREV
2NDHARMD
ANSI08000004-2-en.vsd
ANSI08000004 V2 EN
Figure 92: EF4PTOC (51N/67N) function block
1MRK 502 048-UUS A
Technical manual